1. Field of the Invention
This invention relates to graphics and video processing.
2. Description of Related Art
Graphics and video systems are now being used in various platforms that are beyond the traditional applications. There is a growing need for the integration of computer-generated graphics and real-time video images in applications ranging from personal computers (PC), video conferences, to television (TV) set-top boxes. Demands for these high performance graphics and video processing systems have created many design challenges.
In a typical high performance graphics and video systems, there may be different display systems with different display formats. These different display formats may create many incompatibility problems. These problems are even more significant with the availability of various high definition television (HDTV) formats or standards. Examples of the HDTV formats include 720P (progressive), 1080I (interlaced), etc. Equipment designed for one format may not be able to function properly when displaying the image in another format.
In addition, the need to provide multiple displays on the same screen such as picture in picture (PIP) applications also creates problems in scaling the video image and/or graphics. If an image is not properly scaled to fit in a display screen, image distortion or loss of information may result. The problem is even more significant when images come from sources with different scanning rates. Furthermore, image objects may need to be manipulated such as overlapping, animation. These object manipulations require a flexible object compositing technique that is economical and efficient in terms of memory requirements and processing time.
When the amount of image data is large, especially for high resolution display, memory access becomes a bottleneck. The use of high speed static random access memories for storing entire image sequences is prohibitively costly. Furthermore, to accommodate real-time processing rate, traditional techniques rely on a massive amount of logic and processing elements, resulting in high complexity, high power consumption, and reduced reliability.
Therefore there is a need in the technology to provide an efficient and versatile technique for performing scan rate conversion, scaling and format conversion, de-interlacing, and image object compositing.
The invention is a method and apparatus for processing image data stored in a memory. A read interface circuit is coupled to the memory to transfer a patch of the image data from the memory to a buffer. A scale filter is coupled to the read interface circuit to scale the image data in the patch from the buffer. A receive circuit is coupled to the scale filter to re-organize the scaled image data.